1. Field of the Invention
The present invention relates to furobenzopyran derivatives, a process for their preparation and herbicides containing these compounds as active components.
2. Description of Prior Art
Reports on the synthesis of compounds having a furobenzopyran ring are very few, and there are no reports of such compounds exhibiting herbicidal activity. Only one furobenzopyran derivative that reportedly exhibits a biological activity is monocerin of the following formula: ##STR2##
This compound was first reported in J. Chem. Soc. (C) 2598 (1970) as an antifungal metabolite of Helminthosporium monoceras. Furthermore, this compound is described in U.S. Pat. No. 3,661,935 as an antifungal compound.
O. R. Martin et al. have described a group of compounds of the following formula in Carbohydr. Res., 196, 41-58 (1990): ##STR3##
Further, O. R. Martin has described compounds of the following formulae in Carbohydr. Res., 171, 211-222 (1987): ##STR4##
However, there was no statement as to whether these compounds exhibit herbicidal activity or any other biological activities.
To date, a number of herbicides for use in upland fields and rice paddies have been developed, but none of these is satisfactory in terms of herbicidal activity or herbicidal selectivity in crop farming.